Low-power electric contact

Abstract

A low-power electrical contact particularly suitable for switching and plug-in connections. The contact comprises an outer contact layer and a substrate composed of a copper base alloy. The contact layer consists essentially of an alloy of 35-55% by weight gold, 18-33.5% silver, 30-40% palladium, and (i) 1-6% indium, or (ii) 0.5-2% tin together with 0.5-2% indium. An intermediate layer of nickel or copper-nickel may be interposed between the contact layer and the substrate.

What is claimed is: 
     
       1. A low-power electrical contact comprising an outer contact layer integrally bonded to a substrate, said substrate comprising a copper-base alloy, and said contact layer consists essentially of 39% gold, 22% silver, 37% palladium, and 2% indium. 
     
     
       2. A low-power electrical contact comprising an outer contact layer integrally bonded to a substrate, said substrate comprising a copper-base alloy, and said contact layer consists essentially of 39% gold, 20% silver, 37% palladium, and 4% indium. 
     
     
       3. A low-power electrical contact comprising an outer contact layer integrally bonded to a substrate, said substrate comprising a copper-base alloy, and said contact layer consists essentially of 39% gold, 22.5% silver, 30% palladium, 1% tin, and 0.5% indium. 
     
     
       4. A low-power electrical contact comprising an outer contact layer integrally bonded to a substrate, said substrate comprising a copper-base alloy, and said contact layer consists essentially of 39% gold, 29.5% silver, 30% palladium, 1% tin, and 0.5% indium. 
     
     
       5. The contact of any one of claims 1 through 4, wherein said substrate comprises between 6% and 8% by weight tin and the balance essentially copper. 
     
     
       6. The contact of claim 5, wherein said substrate consists essentially of 94% copper and 6% tin. 
     
     
       7. The contact of claim 5, wherein said substrate consists essentially of 92% copper and 8% tin. 
     
     
       8. The contact of any one of claims 1 through 4, wherein said contact comprises said outer contact layer integral with an intermediate layer of nickel or copper-nickel and said substrate, forming an integral composite of said three layers. 
     
     
       9. The contact of claim 5, wherein said contact comprises said outer contact layer integral with an intermediate layer of nickel or copper-nickel and said substrate, forming an integral composite of said three layers. 
     
     
       10. The contact of claim 6, wherein said contact comprises said outer contact layer integral with an intermediate layer of nickel or copper-nickel and said substrate, forming an integral composite of said three layers. 
     
     
       11. The contact of claim 7, wherein said contact comprises said outer contact layer integral with an intermediate layer of nickel or copper-nickel and said substrate, forming an integral composite of said three layers. 
     
     
       12. A low-power electrical contact comprising an outer contact layer integrally bonded to a substrate, said substrate comprises between 6% and 8% by weight tin and the balance essentially copper, and said contact layer consisting essentially of 35-55% by weight gold, 18-33.5% silver, 30-40% palladium, and (i) 1-6% indium, or (ii) 0.5-2% tin together with 0.5-2% indium. 
     
     
       13. The contact of claim 12, wherein said contact comprises said outer contact layer integral with an intermediate layer of nickel or copper-nickel and said substrate, forming an integral composite of said three layers. 
     
     
       14. A low-power electrical contact comprising an integral composite of three layers bonded together, said composite comprising an outer contact layer integral with an intermediate layer of nickel or copper-nickel and said intermediate layer integral with said outer contact layer and with a substrate, said substrate comprising a copper-base alloy, and said contact layer consisting essentially of 35-55% by weight gold, 18-33.5% silver, 30-40% palladium, and (i) 1-6% indium, or (ii) 0.5-2% tin together with 0.5-2% indium. 
     
     
       15. A low-power electrical contact comprising an integral composite of three layers bonded together, said composite comprising an outer contact layer integral with an intermediate layer of nickel or copper-nickel and said intermediate layer integral with said outer contact layer and with a substrate, said substrate comprising a copper-base alloy, and said contact layer consisting essentially of 20-29.5% by weight silver, 30-37% palladium, and (i) 2-4% indium, or (ii) 0.5-1% tin together with 0.5-1% indium, and the balance gold.